Description: The membership relation is nonempty. (Contributed by AV, 19-Jun-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | epn0 | |- _E =/= (/) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0sn0ep | |- (/) _E { (/) } |
|
2 | brne0 | |- ( (/) _E { (/) } -> _E =/= (/) ) |
|
3 | 1 2 | ax-mp | |- _E =/= (/) |